Douzhanopterus

Douzhanopterus is an extinct genus of monofenestratan pterosaur from the Late Jurassic of Liaoning, China. It contains a single species, D. zhengi, named by Wang et al. in 2017. In many respects, it represents a transitional form between basal pterosaurs and the more specialized pterodactyloids; for instance, its tail is intermediate in length, still being about twice the length of the femur but relatively shorter compared to that of the more basal Wukongopteridae. Other intermediate traits include the relative lengths of the neck vertebrae and the retention of two, albeit reduced, phalanx bones in the fifth digit of the foot. Phylogenetically, Douzhanopterus is nested between the wukongopterids and Propterodactylus, which is similar to Douzhanopterus in many respects but approaches pterodactyloids more closely elsewhere.

==Discovery and naming== The holotype specimen of Douzhanopterus, a skeleton lacking the skull, is preserved on a plate and counterplate. The plate and counterplate are respectively catalogued as STM 19–35A and STM 19–35B, and they are stored at the Shandong Tianyu Museum of Nature in Shandong, China. This specimen was purchased from a local farmer, who claimed that it had been excavated at Toudaoyingzi, Jiangchang in Liaoning province. However, the rock encasing the specimen is characteristic of sediments found at another locality within Liaoning, Linglongta. The latter belongs to the fossil-rich units of the Tiaojishan Formation, which have been dated to 160.89 to 160.25 million years ago, or the Oxfordian stage of the Jurassic period.